Ok, I jewgled this. In the picture linked to this post, look at the part where it is zoomed in on the controller. In between the 2 thumb sticks, you will see a white circle, that is being viewed from a bad angle. It has a black line through it, which is the Xbox logo.. Apparently that white circle is a lit up button, and when the controller is off, there is no light and it looks like a black circle.